The study of serum cortisol in patients prescribed glucocorticoid in Hue University of Medicine and Pharmacy Hospital

Abstract

Background: The adrenal disorders such as adrenal insufficiency and Cushing syndrome may be life-threatening unless patients are diagnosed and treated timely. Taking exogenous glucocorticoid (GC) interfered with the interpretation of the level of serum cortisol in either diagnosis of adrenal insufficiency or evaluation the function of hypothalamic-pituitary-adrenal axis. Objectives: 1) Evaluating the difference between the level of basal serum cortisol before and after taking GC. 2) Evaluating the level of basal serum cortisol in patients who were prescribed physiological dose of GC when withdrawn. Materials and method: This is a cross-sectional study that enrolled patients prescribed GC. It obtained the levels of basal serum cortisol before and after taking GC. In 2nd objective, the level of basal serum cortisol was measured in patients who were diagnosed with GC-induced adrenal insufficiency and prescribed physiological dose of GC when withdrawn temporarily. Results: The values of basal serum cortisol when taking hydrocortisone and prednisolone were higher than before prescribed (p < 0.05). In contrast, the values of basal serum cortisol when taking fluticasone were lower than before prescribed (p < 0.05). Even inhaled fluticasone could affect the level of basal serum cortisol. In GC-induced adrenal insufficiency patients prescribed physiological dose of GC, the group of patients with the values of cortisol when withdrawn < 100 nmol/L accounted for 61.9% while ones with the values 100 - 375 nmol/L accounted for 38.1%. The analysis of ROC curve shows that the duration of physiological-dose-GC prescription could predict the levels of basal serum cortisol when withdrawn and hypothalamic-pituitary-adrenal axis recovery with optimal cut-off of duration is 13 months (Sensitivity: 100%, specificity: 92.3%). Conclusion: Exogenous glucocorticoid could affect the results of basal serum cortisol. The duration of physiologic-dose-GC prescription could predict that hypothalamic-pituitary-adrenal axis recovery in patients with glucocorticoid-induced-adrenal insufficiency could be happened and who could achieve adequate response of Synacthen stimulation test. Key words: cortisol, glucocorticoid, hydrocortisone, methylprednisolone, fluticasone, dexamethasone, cross-reactivity.